What's with Gibberellic Acid

dandy_line(3B (Brainerd, Mn))October 21, 2006

Just a question about Gibberellic Acid. I've never used it but am thinking I am going to have to start buying and using it. Can anyone tell me the ins and outs of using it? How expensive is it? What's the best way to use it? et.

This a hormone that promotes germination in SOME!!! seed. mostly those that require a cold treatment. it will increase % germination & stimulate seedling growth. It is prepared in 100 to 10,000 parts per million. & the seed are soaked in the solution.

Dr. Deno covers Gibberellic acid use pretty well in his book. After reading his report I decided against trying it. It only works well in certain circumstances and only with some seeds. If used too strong or too weak it inhibits germination. I felt I had enough frustration already. Al

"It only works well in certain circumstances and only with some seeds."

A "one size fits all" approach to seed germination might be simpler, but different seeds have different needs with respect to light or dark, cold or warmth, etc.

However, I agree with you that unless you have good reason to believe that GA-3 will help with a particular seed, I probably wouldn't use it on that seed. But if someone's experiments have indicated that GA-3 helps with a particular seed, I would be willing to try it, too.

The J. L. Hudson site, in the "Other Areas for Research" section, mentions that Potassium nitrate (KNO3) is often used to stimulate germination of dormant or irregular seeds. Hydrogen peroxide stimulates many species. Presoaking seeds in malt extract or in beer may increase germination and vigor, especially of old seeds, due to enzyme engrichment. Citric acid has been used to stimulate germination in some species, as has a weak solution of household bleach. Combined treatments such as KNO3 and GA-3 or hydrogen peroxide and GA-3 have in some cases given higher germination than with either treatment alone.

However, like you, I don't have time to do a lot of experiments and would like to have specific recommendations for specific seeds. I do have some old zinnia seeds that, out of desperation, I may try GA-3, KNO3 and malt extract on.

I find GA-3 is rather fun to play with, and necessary with a few seeds, and extremely useful for some. For example, unless you like to try your luck with some gentians and/or wait for a lont time for them to germinate, GA-3 is pretty darn helpful to germinate them much sooner, and no cold-period needed in most cases. Some violas are extremely hard to germinate without it, and a few won't even germinate at all without it (as well as a few other genera/species). I had trilliums (which take a loooooong time to germinate) germinate in about six months and only one cold period with GA-3. It's not useful for most things, but pretty darn useful for many hard-to-germinate desirable species, and from almost necessary to essential for others.

The catch is that it is pricey for the amount you get, but you need so little of it per use that chances are you won't go through a single little packet even if you're trying to populate your farm with all rare species. The problem is also that the amount needed per use isn't quite an exact science yet (I don't think anyone's ever done a proper study of the quantities needed for individual species, but the Deno book does help), so you may be going through some trial and error, although the standard dilutions given by Deno and JL Hudson are usually good enough. They also give good methods for its use.

I haven't had time to try out other methods, but I've been dying to try them. Another method I've heard is possibly using smoke, which is necessary for some species (proteas, etc.), but may be helpful for many other species. The active ingredient isn't quite pinned down yet. You can use "liquid smoke" you can find in cooking stores for flavouring, I hear.

If you're Canadian, you can also get GA-3 from Gardens North in Ontario.

If you're curious about GA-3, I would recommend trying it for the fun of it or to germinate some unusual plants. Do make sure the seeds you want to germinate need it or are helped by it, though, and it can kill most common seeds.

For those seeds that require smoke to germinate, I have used Kirstenbosch "Instant Smoke Plus" Seed Primer. It is a product of South Africa, available from Australian Seed Exporters email dorriel@iinet.net.au. This is small paper disc which have been impregnated with smoke chemicals. The paper is soaked in water to release the chemicals into the water. The seed is then soaked in the water, after which it is planted. I have had excellent germination of very difficult seed. Al

Thanks for all the responses. I've kept stumbing across it on various web sites but didn't really know how it was used. I will probably give it a try since I'm wasting about $50 worth of seed every year due to poor/no germination rates. Some things are particularly vexing and they shouldn't be. Maybe next year I can get some Rodgersia to make into the garden.

I have been able to germinate rodgersia with little problem, got some from hardyplants.com Tiny seeds,best started now indoors since it is very slow growing, do not cover, I did in plastic covered pot.
Am planning to try GA-3 myself. Not that I have space left in my garden but just for fun of making those seeds work ;)

Ok on the Rodgersia. I am a big fan of HardyPlants.com. Have bought seeds there for the last 3 years now. What A great inventory they have. I think they're up to 2500 species or so. Just about everything imaginable.
My Rodgersia seems to germinate, then the seedlings slowly dies over time before I can get them into the ground. This is frustrating.